What is the best excercise to builds up abs if you are a 19 year old girl and we!

What is the best excercise to builds up abs if you are a 19 year old girl and weigh 175 pounds?

First do lots of cardio- cycling, elliptical and treadmill or running outside. That's going to bring down your body fat to help make your abs more visible .Do this 4-5 times a week and add in Pilate's or kick boxing because they make all of your core muscles strong - at least 3 times a week. Also watch your diet ,calories and carbs.Try drinking alot of water and avoid gassy foods that will make you bloated .There is also this little trick to help you remember to tighten your stomach muscles.Drawl in your ab muscles and tie a string around your waist that way every time you loosen your muscles the string will tighten reminding you to drawl your muscles back in and soon it will be a habit and youll be working them with out thought.